The commandment that the second Pesach (Pesach Sheni)-offering be eaten with matsot and marror (bitter herbs): That anyone who is obligated in Pesach Sheni eat from the meat of the Pesach-offering with matsot and bitter herbs, as it is stated (Numbers 9:11), “They shall eat it with unleavened bread and bitter herbs.”
[Concerning] the roots of the commandment, I have written about all of the matter of Pesach in the Order of Bo el Pharaoh (Sefer HaChinukh 5). And there is no doubt that the entire matter of Pesach Sheni is all from the foundation of the first — the thing is well-known.
From the laws of the commandment — that which they, may their memory be blessed, said (Pesachim 40a) that matsot require great watching, that they not come to rising, to the point that they, may their memory be blessed, obligated us to be careful that no water come upon [the wheat], even from the time of reaping, lest it come to rising (Mishneh Torah, Laws of Leavened and Unleavened Bread 5:9); and the rest of its details — are [all] elucidated in [the] first [section of] Pesach[im]. And the general rule is that there be a great guarding upon them that they not come to rising. And so [too,] what they explained about marror, that any bitter (mar) herb is included in the marror mentioned by the verse, and that a person fulfills his obligation on Pesach with any of them. As the commandment to us about marror is in memory of “they made life bitter for them” (Exodus 1:14), and the matter is remembered with any bitter herb. But nonetheless, the Sages, may their memory be blessed, chose for us (Pesachim 39a) to eat romaine lettuce. As with it, there is memory of the bitterness through the stalk, the taste of which is a little bitter, and there is also more beauty to the commandment than with other bitter herbs. And also its name is beautiful, as it is called chassah, [such that] a blessing is hinted in it — that the Merciful One pitied (chass) us and redeemed us from the hand of the harsh Egyptians. And from all of these [angles] there is arousal and remembrance in the heart of people of the matter of the miracles that were done for us in Egypt. And therefore, the law was fixed that it is fitting for us to look for romaine lettuce. Its details are also found in Pesachim.
And [it] is practiced at the time of the [Temple] by males, but not by females. As just like the slaughtering of the Pesach Sheni sacrifice is not obligatory [for them], but optional — as we said in the previous commandment — so too is the eating of matsah and marror with it not obligatory for them. And this is also elucidated there in Tractate Pesachim 95a. And one who transgresses this and eats the Pesach Sheni sacrifice without matsah and marror has violated this positive commandment.
מִצְוַת פֶּסַח שֵׁנִי שֶׁיֵּאָכֵל עַל מַצּוֹת וּמְרוֹרִים – שֶׁכָּל הַמְּחֻיָּב בְּפֶסַח שֵׁנִי שֶׁיֹּאכַל בְּשַׂר הַפֶּסַח עַל מַצּוֹת וּמְרוֹרִים, שֶׁנֶּאֱמַר (במדבר ט יא) עַל מַצּוֹת וּמְרֹרִים יֹאכְלֻהוּ.
The commandment that the second Pesach (Pesach Sheni)-offering be eaten with matsot and marror (bitter herbs): That anyone who is obligated in Pesach Sheni eat from the meat of the Pesach-offering with matsot and bitter herbs, as it is stated (Numbers 9:11), “They shall eat it with unleavened bread and bitter herbs.”
מִשָּׁרְשֵׁי מִצְוַת כָּל עִנְיַן הַפֶּסַח כָּתַבְתִּי בְּסֵדֶר בֹּא אֶל פַּרְעֹה (מצוה ה), וְאֵין סָפֵק כִּי כָּל עִנְיַן פֶּסַח שֵׁנִי אֵינוֹ כִּי אִם מִיְּסוֹדוֹ שֶׁל רִאשׁוֹן, יָדוּעַ הַדָּבָר.
[Concerning] the roots of the commandment, I have written about all of the matter of Pesach in the Order of Bo el Pharaoh (Sefer HaChinukh 5). And there is no doubt that the entire matter of Pesach Sheni is all from the foundation of the first — the thing is well-known.
מִדִּינֵי הַמִּצְוָה. מָה שֶׁאָמְרוּ זִכְרוֹנָם לִבְרָכָה (פסחים מ, א) שֶׁהַמַּצּוֹת צְרִיכוֹת שִׁמּוּר גָּדוֹל שֶׁלֹּא יָבֹאוּ לִידֵי חִמּוּץ, עַד שֶׁחִיְּבוּנוּ זִכְרוֹנָם לִבְרָכָה (רמב"ם חמץ ומצה ה ט) לְהִזָּהֵר בָּהֶם אֲפִלּוּ מִזְּמַן קְצִירָה שֶׁלֹּא יָבוֹאוּ עֲלֵיהֶן מַיִם, פֶּן יָבוֹאוּ לִידֵי חִמּוּץ. וְיֶתֶר רִבּוּי פְּרָטֵיהֶן בְּעִנְיַן הַלִּישָׁה וְהָאֲפִיָּה בְּפֶסַח רִאשׁוֹן, וּכְלַל הַכֹּל הוּא, שֶׁנַּעֲשֶׂה בָּהֶן שְׁמִירָה גְּדוֹלָה מֵחִמּוּץ. וְכֵן מָה שֶׁפֵּרְשׁוּ בַּמְּרוֹרִים שֶׁכָּל עֵשֶׂב מַר הוּא בִּכְלַל מְרוֹרִים שֶׁהִזְכִּיר הַכָּתוּב, וְשֶׁאָדָם יוֹצֵא יְדֵי חוֹבָתוֹ בַּפֶּסַח בְּכֻלָּן, לְפִי שֶׁהַצַּוָּאָה לָנוּ בְּמָרוֹר, זֵכֶר לְוַיְמָרְרוּ אֶת חַיֵּיהֶם (שמות א יד), וּבְכָל עֵשֶׂב מַר יִזְכֹּר הַדָּבָר. אֲבָל מִכָּל מָקוֹם בֵּרְרוּ לָנוּ חֲכָמִים זִכְרוֹנָם לִבְרָכָה (שם לט א) לֶאֱכֹל הַחֲזֶרֶת, כִּי בָּהּ זֵכֶר הַתַּמְרוּר מִצַּד הַקֶּלַח שֶׁטַּעְמוֹ מַר קְצָת, וְגַם יֵשׁ בָּהּ הִדּוּר לְמִצְוָה יוֹתֵר מִבִּשְׁאָר עֲשָׂבִים מָרִים, גַּם כִּי שְׁמָהּ הָדוּר שֶׁנִּקְרֵאת חַסָּא, וְרֶמֶז בְּרָכָה בּוֹ שֶׁחָס רַחֲמָנָא עָלֵינוּ וּפְדָאָנוּ מִיַּד הַמִּצְרִיִּים הַקָּשִׁים, וּמִכָּל אֵלֶּה יֵשׁ הִתְעוֹרְרוּת וְזֵכֶר אֶל לֵב בְּנֵי אָדָם בְּעִנְיַן הַנִּסִּים שֶׁנַּעֲשׂוּ לָנוּ בְּמִצְרַיִם, וּלְפִיכָךְ הֻקְבְּעָה הַהֲלָכָה שֶׁרָאוּי לָנוּ לְחַזֵּר אַחַר הַחֲזֶרֶת. פְּרָטֶיהָ גַּם כֵּן בְּמַסֶּכֶת פְּסָחִים [שם].
From the laws of the commandment — that which they, may their memory be blessed, said (Pesachim 40a) that matsot require great watching, that they not come to rising, to the point that they, may their memory be blessed, obligated us to be careful that no water come upon [the wheat], even from the time of reaping, lest it come to rising (Mishneh Torah, Laws of Leavened and Unleavened Bread 5:9); and the rest of its details — are [all] elucidated in [the] first [section of] Pesach[im]. And the general rule is that there be a great guarding upon them that they not come to rising. And so [too,] what they explained about marror, that any bitter (mar) herb is included in the marror mentioned by the verse, and that a person fulfills his obligation on Pesach with any of them. As the commandment to us about marror is in memory of “they made life bitter for them” (Exodus 1:14), and the matter is remembered with any bitter herb. But nonetheless, the Sages, may their memory be blessed, chose for us (Pesachim 39a) to eat romaine lettuce. As with it, there is memory of the bitterness through the stalk, the taste of which is a little bitter, and there is also more beauty to the commandment than with other bitter herbs. And also its name is beautiful, as it is called chassah, [such that] a blessing is hinted in it — that the Merciful One pitied (chass) us and redeemed us from the hand of the harsh Egyptians. And from all of these [angles] there is arousal and remembrance in the heart of people of the matter of the miracles that were done for us in Egypt. And therefore, the law was fixed that it is fitting for us to look for romaine lettuce. Its details are also found in Pesachim.
וְנוֹהֶגֶת בִּזְמַן הַבַּיִת, בִּזְכָרִים וְלֹא בִּנְקֵבוֹת, כִּי כְּמוֹ שֶׁאֵין שְׁחִיטַת פֶּסַח שֵׁנִי חוֹבָה לָהֶן אֶלָּא רְשׁוּת, כְּמוֹ שֶׁאָמַרְנוּ בַּמִּצְוָה הַקּוֹדֶמֶת, כֵּן אֲכִילַת מַצָּה וּמָרוֹר עִמּוֹ אֵינָהּ חוֹבָה לָהֶם, וּמְבֹאָר גַּם זֶה שָׁם בְּמַסֶּכֶת פְּסָחִים (צה א). וְהָעוֹבֵר עַל זֶה וְאָכַל פֶּסַח שֵׁנִי מִבְּלִי מַצָּה וּמָרוֹר בִּטֵּל עֲשֵׂה זֶה.
And [it] is practiced at the time of the [Temple] by males, but not by females. As just like the slaughtering of the Pesach Sheni sacrifice is not obligatory [for them], but optional — as we said in the previous commandment — so too is the eating of matsah and marror with it not obligatory for them. And this is also elucidated there in Tractate Pesachim 95a. And one who transgresses this and eats the Pesach Sheni sacrifice without matsah and marror has violated this positive commandment.